ZHANG Ai-kui1,2, MO Xuan-xue1, YUAN Wang-ming1, LIU Guang-lian2, ZHU Chuan-bao2, HAO Na-na1
(1. College of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083, China;
2. No. 3 Exploration Institute of Geology and Mineral Resources of Qinghai Province, Xining 810029, China)
Abstract: As a component of continental crust, granites are very important for unraveling the formation and evolution history of ocean basin closure and continents. Triassic granite is widely distributed in the Yemaquan area of the western part of the Eastern Kunlun Mountain Range, P.R. China. The petrogenesis and tectonic setting of granite in Yemaquan area have been poorly studied. Based on the petrology, geochemistry, and geochronology of the granitoids, authors consider that the syn-collisional orogenic stage of the late Paleozoic－early Mesozoic is 235－224 Ma, and post-collisional orogenic stage is 224－204 Ma. Associated with intrusive rocks in syn-collisional orogenic stage are quartz monzodiorites-granodiorites. These rocks are classified as calc-alkaline－high K calc-alkaline series and metaluminous-weakly peraluminous I-type granite. They formed in the lower crust or mid-lower crust, related to underplating of mantle material and delayed partial melting of the subduction oceanic material. Granodiorites are similar to the adakitic intrusive rocks. Associated with the intrusive rocks in post-collisional orogenic stage are porphyritic monzogranite- granite porphyry. These rocks are classified as high K calc-alkaline-shoshonitic series and metaluminous- strongly peraluminous S-type granite. They formed in the upper crust. The granite source region of monzogranite including dioritic enclaves, has the signs of EMⅡ, different from other monzogranite. Yemaquan Triassic granite formed as the deep course of mantle underplating, “lag-type” oceanic material partial melting and crust partial melting.
Keywords: Triassic granite; petrogenesis；granitoids tectonic setting; Yemaquan area; Kunlun Mountain
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ACTA MINERALOGICA SINICA Vol. 36, No. 2, 2016, Page 157-173
